The 35 f1.8DX is a bargain and is capable of great results, plus its large aperture and fixed focal length make it a very creative tool. That would always be my first recommendation. Despite having 5 Zeiss primes and more expensive Nikon's it is often my choice for days out and especially travel.

I recently tested a friend's 18-105 on his D7000 while trying to fine tune focus and optically at the long end especially, it was well below what the sensor is capable of delivering and below what I would want or expect (bad copy?) I did have the 18-135 with D80 a few years back and although it was very sharp it had big distortion, vignetting and serious build quality issues...needed repair/replacement 3 times due to focus motor and inner barrel issues.